Electric Dreams

How do you measure the movements and social interactions of exotic tropical fish swimming in the murky waters of the Amazon river basin? LIMBS lab members Dr. Manu Madhav and Ravi Jayakumar developed a new tool to do just that for weakly electric fish. With the help of former lab members Alican Demir and Sarah Stamper and in close collaboration with Dr. Eric Fortune from NJIT, Manu and Ravi developed the “grid”, an array of custom electrodes that sits just below the surface of the water, along with a custom software system that “triangulates” the locations of individual fish. This was featured in the the Johns Hopkins Magazine, Winter 2018 Edition.

The work was published in the open-access journal, Scientific Reports:

  • [PDF] [DOI] M. S. Madhav, R. P. Jayakumar, A. Demir, S. A. Stamper, E. Fortune, and N. J. Cowan, “High-resolution behavioral mapping of electric fishes in Amazonian habitats,” Sci Rep, vol. 8, iss. 1, p. 5830, 2018.
    author = {Manu S. Madhav and Ravikrishnan P. Jayakumar and
    Alican Demir and Sarah A. Stamper and Eric
    S. Fortune and Noah J. Cowan},
    title = {High-resolution behavioral mapping of electric
    fishes in Amazonian habitats},
    journal = {Sci Rep},
    number = 1,
    volume = 8,
    year = 2018,
    pages = {5830},
    doi = {10.1038/s41598-018-24035-5},
    url = {http://www.nature.com/articles/s41598-018-24035-5}
Illustration of a grid to detect electric fish

2018 is Banner Year for LIMBS Lab Research Grants

LIMBS Laboratory receives unprecedented funding

Multiple grants to study spatial representations in the brain with Jim Knierim

In collaboration with Jim Knierim, professor of neuroscience at the School of Medicine and the Krieger Mind/Brain Institute at Johns Hopkins University, we aim to further our understanding of the hippocampus, a component of the brain that plays a major role in learning, memory, and spatial navigation.The team has recently funding from two NIH grants, as well as a part of a $7.5M Multidisciplinary University Research Initiative (MURI) project spearheaded by Daniel Koditschek (PI). Together the JHU Team’s research grant awards total about $5M to Johns Hopkins University.

Multiple grants to study human sensorimotor control with Amy Bastian.

Teaming up with Amy Bastian, the LIMBS laboratory has secured funding from the NIH and NSF to investigate visuomotor control in patients with cerebellar ataxia. One of these projects is a collaboration with Jim Freudenberg and Brent Gillespie at the University of Michigan.

Details of current awards to the LIMBS Laboratory

  • ARO #72929-EG-MUR: 09/01/2018–08/31/2023. “Science of Embodied Innovation, Learning and Control.” Investigators: Daniel E. Koditschek (U Penn, PI); Juliy Baryshnikov (UIUC), Robert J. Full & Lucia Jacobs (UC Berkeley), and Noah J. Cowan and Jame J. Knierim (JHU). Award: $7,500,000 (Subaward to JHU: $956,999).
  • NSF #1830893: 09/15/2018–08/31/2022. “EFRI C3 SoRo: Programming Thermobiochemomechanical (TBCM) Multiplex Robot Gels.” Investigators: David Gracias dgracias@jhu.edu (PI), Noah Cowan, Thao (Vicky) Nguyen, Rebecca Schulman. Award: $2,000,000 (Suballocation to NJC: ≈$500,000)
  • NIH-NINDS 2R01HD0402859-15: 09/01/2017–08/31/2022. “Mechanisms and Rehabilitation of Cerebellar Ataxia.” Investigators: Amy J. Bastian (KKI, PI) and Noah J. Cowan Agency: National Institutes of Health–NINDS.” Award: $30,000 (Amount of Subaward from KKI to Cowan, JHU).
  • NSF #1825489: 08/01/2018–07/31/2021. “Collaborative Research: Identifying Model-Based Motor Control Strategies to Enhance Human–Machine Interaction
    Investigators.” James S. Freudenberg (PI), Noah J. Cowan, R. Brent Gillespie, and Amy J. Bastian Award: $381,470 (Amount to Cowan, JHU/KKI).
  • NIH-NIMH 1R01MH118926-01: 7/01/2018–3/31/2023. “CRCNS Research Proposal: Collaborative Research: Dynamics of Gain Recalibration in the Hippocampal-Entorhinal Path Integration System.” Investigators: James J. Knierim (PI), Noah J. Cowan, Kechen Zhang, and Kathryn R. Hedrick. Award: $1,488,302 (Suballocation to NJC: $547,227)
  • NIH-NINDS 1R21NS103113: 07/01/2017–06/30/2019. “Using Feedback Control to Suppress Seizure Genesis in Epilepsy.” Investigators: Sridevi Sarma (PI), Noah J. Cowan. Award: $410,437 (To NJC: ≈$29,000).
  • NIH-NINDS 5R01NS102537-02: 07/01/2017–06/30/2022. “A Control Theoretic Approach to Addressing Hippocampal Function.” Investigators: Noah J. Cowan (PI) and James J. Knierim. Award: $2,095,459 (≈ split between PI’s).
  • NSF-IOS #1557858: 04/01/2016–03/31/2020. “Collaborative Research: Neural Mechanisms of Active Sensing Investigators: Noah J. Cowan (PI) and Eric S. Fortune.” Award: $425,000 (To JHU)

Brittany Nixon wins second place at NSF REU Presentation Contest!

LIMBS Lab summer REU student Brittany Nixon won Second Place out of 15 talks at the annual JHU / LCSR Summer REU Program for her excellent oral presentation entitled “A Mathematical Model of the Fish Tracking Response of the Weakly Electric Glass Knifefish”. Special thanks to her mentor Ismail Uyanik.


Left: A day in the lab. Right: Brittany & Ismail at Brittany’s poster the day before.

Brittany joins a long list of successful REU students from the LIMBS lab!

2010: Rohan Ramesh (1st Place), Rachel Jackson (2nd Place)
2012: Daniel Price (1st Place)
2016:  Luke Arend (1st Place)
2018: Brittany Nixon (2nd Place)

Virtual reality alteration of visual feedback in cerebellar patients can improve reaching

Amanda Edwards’s presentation at the OSU MBI Workshop: CONTROL AND MODULATION OF NEURONAL AND MOTOR SYSTEMS, September 12, 2017:


Abstract: People with damage to their cerebellum often exhibit “reaching ataxia”, or misdirected, poorly scaled movement patterns which are reminiscent of a poorly tuned control system. Ataxia affects most all activities of daily living (e.g. eating, cooking, bathing, dressing, working). It is believed that these patients have a static, miscalibrated internal model of their body dynamics; however, it is unknown whether their feedback control is intact. We challenged these participants with visuomotor system identification tasks in order to model their feedback control architecture. Our results suggest that cerebellar patients have intact feedback control, but are forced to rely on time-delayed visual feedback. The key difference is that healthy subjects seem to be able to compensate for their visuomotor delay suggesting that the cerebellum may be serving the role of a Smith predictor for this task. Finally, we were able to leverage the cerebellar patients intact visuomotor feedback control system to improve the scaling of these movements by altering their visual feedback based on their real-time movement in a virtual reality environment.

Introducing Dr. Erin Sutton!

On July 6, 2016, Erin Sutton successfully defended her PhD Dissertation “Bioelectric Sensing and Navigation: Multimodal Control in Electric Fish and Endovascular Interventions”, becoming the 10th PhD graduate of the LIMBS Laboratory.

Congrats Erin!

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